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2 Sheets-Sheet 1 PRIMER ANV IL J. A. MURPHY Filed July 27 1923 Sept. 14 1926.

c/wuuw a. 7771077177 Patented Sept. i l, lfifid JAMES A. MURPHY, OF LOWELL, MASSACHUSETTS, ASSIGNOR TG UNITED STATES CARTRIDGE 00., OF LOWELL, MASSACHUSETTS, A CORPORATION OF MASSACHU- snr'rs.

PRIMER ANVIL.

Application filed July 27,

In the manufacture of anvils for the primers in explosive cartridges, such as shells for rifles, certain modifications of design and principle have become necessary as a result 5 of using smokeless powders instead of the older black powder mixtures. Among these may be primarily mentioned the need of a somewhat greater amount of fulminate in the primer and a consequently greater air and expansion chamber in the primer. It has also been found desirable that the fulminate be ignited or exploded by a quick, conceutrated percussion from the hammer of the gun. To this end it is necessary that 5 the anvil shall be firmly held in the primer, both laterally and longitudinally of the shell, and that it shall give a direct, percussive blow to the fulminate.

It is therefore an object of my invention to provide a primer anvil which shall meet such requirements, and a process whereby they may be produced. It is further an olo- .ject of my invention to devise an anvil which shall be of minimum volume but with ample strength and sufficient bearing surface to meet the requirements of usage. It is also an object of my invention to provide a method of producing such anvils simply and quickly from metallic sheets or strips.

0 T have discovered that primer anvils, which meet all of the above conditions, may be made simply and rapidly from metal strips, by a two-stage process. In general this process involves a preliminary stage of 5 indenting one side of the metal strip to the desired shape, simultaneously raising and molding the corresponding opposite side of the strip to a predetermined contour and a second stage in which the portion so shaped .0 'shall be cut from the strip. The primer anvils thus obtained are of regular size and shape, and the edges and surfaces are clearly delined and meet all of the conditions above set forth;

Vvithout limiting the scope of my invention, I shall describe a preferred mode of operation thereof, reference being made to the followings drawings in which V Fig. 1 is a cross-section of a sheetof metal in which one portion thereof is being shaped.

and another previouslyshaped portion there of is be ng cut out;

Fig. 2 is a cross-section of the elements of 1923. Serial N0. 654,170.

Fig. 1 with the punches in raised position and showing an extruded anvily,

Fig. 3 is a cross-section of the punch along the line 3+3 of F ig. 1;

Fig. d is a plan view of the metal strip showing indentations therein produced by the first stage of the process and apertures left after the out; i

Fig. 5 is a section on line 5-5 of Fig. 2;

Fig. 6 is a section on line 66 of'Fi 2; lFig. 7 is a plan View of the complete an- V1 8 is a bottom view of the completed anvi 9 is a side view of the completed an- Fig. 10 is a side view of the completed anvil at 90 to Fig. 9; i

Fig. 11 is a longitudinal cross-section-of a shell and primer in which; an anvil is mounted ready for use; and I Fig. 12 is a cross-section of a shell at 90 to the cross-section of Fig. 11.

In the application of my invention, I employ a strip of malleable metal 10, preferably of brass and relatively thin, for example not over thick. This may be a broad sheet or, as shown, a strip of sufiicient width to cut one row only of anvils therefrom. This strip is fed, by any suitable means, across the die 1 with which the punch 2 registers, and thence over the aperture 3 in the block 4 into which the punch 6 fits closely as will be clear from Figs. 1 and 3. The shaping punch 2 descends under pressure, forcing the lower surface of the sheet to conform to the surface of the block 1 and the upper surface to conform with the contours of the shaping punch 2. The punch is then raised as shown in Fig. 2 leaving the indentation 7 having an ovoido-oonical bottom 8, an annular shoulder 9, and a fiat surface finished anvil has been stamped" 11 surrounding said indentation, and on the opposite side the raised portion 15, which has substantially the shape of a truncated cone, with a cylindrical projection 16 at the gpeivP- and an annular shoulder 17 near the ase.

The indentation is subsequently moved into centered relation over the aperture 3 in the punching block 4, The punch 6 which is similar in contour to shaping punch 2 is then lowered under pressure and by its shearing action in entering the aperture 3 cuts a portion from the sheet corresponding in shape to the sectional view of the punch as shown by Fig. 5, or to the remaining aperture 28 shown in Fig. 4. The anvil. thus shaped and cut from the metal strip, is forced through the aperture 3 as shown in Fig. 3, through which it drops by gravity as shown in Fig. 2.

The shaping and cutting punches 2 andG are raised after each of these operations and the. strip moved forward a fixed distance,

'when they are again lowered as before. 15.

These punches are refer-ably lowered and raised simultaneousy and being. properly spaced and the strip being fed under thenr a suitable distance between each stroke the cuttingpunch 6 will register with the impressions 20 previously made by the shapmg punch 2 in the metal strip, cuttingoat the anvils and leaving openings 28 as shown by Fig. 4.

The primer anvil thus produced, as shown in plan View by Fig. 7 and in reverse by Fig. 8- has diametrically opposite grooves or notches 21, a sharply defined protruding boss 16 as shown in Figs. 9 and 10, coneshaped sides 15 and 17, cylindrical bearing surfaces 27 and 2S and flat bearing surfaces 29 and 30 at-right angles to its axis.

InFigs. 11 and 12 the anvil .35 is shown as mounted in the primer of a shell having cylindrical depression 41, and an opening 42 therein leading to the chargingchamber 43. The anvil 35 is shown'with its fiat bearing surfaces 29 and 30 spanning the opening 42 and resting against the i bottomportion 45 of. the depression 41.

Surrounding the anvil within the d pression 41 is the usual cylindrical primer cap 47 containing a layerof fulminate 48 covered with a paper disc 49, against which the boss of the anvil contacts.

As thus. assembled, the advantages of the ;primer anvil produced by my process are readily apparent. Theflat bearing surfaces 29 and 30 seat squarely against the bottom of the primer cavity, and the cylindrical bearing surfaces of the anvil fit snugly against the cylindrical inner surface of the primer cap. The conical shape of the anvil leaves a maximum gas space between it and the fulminate charge andalso within its conical cavity. The notches in the pcriphery permit the immediate passage of the combustion gases from the ignited fulminate into the explosive charge of the shell.

When the shell is placed in a gun and the hammer of the gun strikes the primer'cap l? which is thrust inwardly of the cartridge the anvil, because of the firm bearing of its cylindrical and end bearing surfaces remains stationary, and the shock is concentrated between the apex 'ofthe anvil and the Itis also to be noted that by indenting.

the anvil with the conical dcpressionhavmg acute interior conical surface 8 and an obtuse onical externalface 15, the 'struc-' ture of the wholeis very much st engthened and enabled to more rigidly receive and transmit the hammer blowof the gun to the fulminate cap. Both the general hollowconical shape of theanvil and the difference in the conical angles of these. two surfaces result, iinlcpeiulently and together, in. com

tributing to the rigidityof the whole anvil.

The shoulder or annular countersunk portion 9, likewise'adds to the air-space chain-- berot the cap and helps to make'the surface 11 broader and to form its inrredges. at right angles to the conical aX1s.

hloreover, this construction permits deep cutting of t-henotches 21 as far as,- or even beyond, the inner conical surface, thus leav:

ing a treeair space and opening into themnerxehamber lS, without appreciably de creasing thestrengthzonrigidity of the primer anvil.

The manufacture of my anvilfby two stages or steps of operation accomplishes results which are not obtainable by the one operation methods commonly employed, nor

by those methods in which the anvil:is-

shaped after being cut out. Not only do such processes involve complicated mechanical motions, but the finished product does not have the characteristics of the anvils made accordingto my' process. I 'is well known that when a sheetof metal isindented or bent. thereis a relative movement I of the metal along the margins of'such indentations orbends Moreover, if such bends are made near the square edges of a metal sheet, these edges will be deformed. Therefore. if anvils' such as described were to be shaped from previously cut out discs the square or cylindrical edges 27 28 would: not remain cylindrical and form right angles with surfaces 29,80, but would be deformed and present a sloping surface for contact with the cylindrical interior surface'ofthe primer cap 47, bearing. upon it byan edge or points of contact instead of by the broad surface as shown.. In thepresent invention,

however, such deformation is avoidable by 1 ltl dill

the positive, vertical cutting action of punch 6, the face of which exactly fits the previously shaped surface of the anvil, aftr shaping it from the metal sheet has been complished.

it claim:

l. A primer comprising an il'lVll of conical type formed from sheet metal and having inside and outside tapered surfaces, the thickness of the anvil at its periphery being approximatelyequal to the thickness of said sheet and the inside surface extending into the outside taper axially of the anvil, notches extending from the periphery through tapered portions of the anv1 l,'and a percussion cap telescoping over said periphery.

2. A primercomprising an anvil of conical type formed from sheet metal and havin inside and outside tapered surfaces, the

thickness of the anvil at its periphery being approximately equal to the thickness of said sheet and the inside surface extending into the outside taper axially of the anvil, notches extending from the periphery through tapered portions of the anvil, the anvil having on its base end bearing surfaces of substantial radial dimensions, and a percussion cap telescoping over said periphery.

3. A hollow primer anvil formed from sheet metal and having inside and outside tapered surfaces, the thickness of the anvil at its periphery being approximately equal to the thickness of said sheet and the inside surface extending into the outside taper axially of the anvil, notches extending from the periphery through tapered portions of the anvil and a protuberance at the apex of the outside tapered surface.

A primer comprising an anvil formed from sheet metal and having inside and outside tapered surfaces and inside and outside surfaces which are approximately cylindrical, the thickness of the anvil at its peripherybeing approximately equal to the thickness of said sheet and the inside surface extending into the outside taper axially of the anvil, notches extending from the periphery through tapered portions of the anvil, and a percussion cap telescoping over said outside cylindrical surface.

5. A primer comprising an anvil of conical type formed from sheet metal and hav ing inside and outside tapered surfaces, the thickness of the anvil at its periphery being approximately equal to the thickness of said sheet and the inside surface extending in to the outside taper axially of the anvil, notches in the base of the anvil, the anvil having on its base end surfaces extending transversely of its axis, and a percussion cap telescoping over said periphery.

G. A hollow primer anvil formed from thin sheet metal and having, both on the inside and the outside, surfaces which are approximately cylindrical and conical respectively, and having notches extending inwardly from it periphery through both outside cylindrical and conical surfaces and also through the inside cylindrical surface.

7. A primer comprising an anvil of conical type formed from sheetmetal and having inside and outside tapered surfaces, the thickness of the anvil at its periphery being approximately equal to the thickness of said sheet and the inside surface extending into the outside taper axially of the anvil, the base of the anvil having bearing surfaces approximately in a plane perpendicular to its axis, and a percussion cap telescoping over said periphery.

S. A primer anvil for use in a primer chamber which is circular in cross section and communicates through an opening concentric therewith with a charge chamber, comprising a body having the general shape of a truncated hollow cone, the hollow phrtion of said body being generally conical and having an internal diameter at its base larger than that of the opening from the primer chamber, and said body having notches out in the peripheral margins thereof intersecting said hollow portion.

9. A primer anvil for use in a primer chamber which is circular in cross section and communicates through an opening concentric therewith with a charge chamber,

.comprising a body having a generally conical exterior and provided with a conical coaxial recess in its interior communicating with a cylindrical recess of greater diameter, said latter recess adapted to overlie the opening connecting the primer and charge cham-' bers and being of greater diameter than the opening, and said body having notches cut in the peripheral margins thereof intersecting said conical recess.

Signefl by me at Lowell, Massachusetts, this th day of June, 1923.

JAMES A. MURPHY. 

